1. Technical Field
The present invention relates to a production method of a gas cell, and a gas cell.
2. Related Art
As a biomagnetism measuring apparatus which detects a magnetic field emitted from the heart of a living body or the like, an optical pumping type magnetic sensor has been used. JP-A-2009-236599 discloses a magnetic sensor using a gas cell, pump light, and probe light. In the magnetic sensor, atoms sealed in the gas cell are excited by the pump light and cause spin polarization. Since the polarization plane of the probe light transmitted by the gas cell is rotated according to a magnetic field, the magnetic field is measured using the rotation angle of the polarization plane of the probe light.
JP-A-11-238469, U.S. Pat. No. 7,666,485, and “A Technique for preparing Wall Coated Cesium Vapor Cells” in The Review of Scientific Instruments, Vol. 43, No. 9, pp. 1388-1389 (1972) by Grbax Singh, Philip Diavore, and Carrol O. Alley, disclose techniques for filling a cell with a gas.
When a plurality of gas cells are produced, if characteristics of the gas cells vary, this is reflected in the variations of the sensitivity of the magnetic sensor.